Polishing wheel



E. B. A. BLOUNT May 5, H36.

POLISHING WHEEL Filed April 20, 1935 Patented May 5, 1936 UNITED STATES PATENT OFFICE Application April 20,

Claims.

My invention relates to polishing wheels for polishing slabs or blocks of stone.

The principal objects of the invention are to provide a wheel by which the polishing operation may be rapidly efiected, which does not throw off the sludge used in the process of grinding or polishing and in which danger of a workman being injured by a scroll thrown from the wheel is substantially eliminated.

A principal feature of the invention consists in constructing the polishing wheel as a rotatable disk having upon its working face a plurality of sets of scrolls each including a curved outer scroll having an abrupt change in its direction, the leading end of each outer scroll terminating in advance of the point of abrupt change in direction of the outer scroll of the next preceding set.

Another primary feature of .the invention consists in constructing the polishing wheel as a rotatable disk having upon its working face a plurality of sets of scroll members or flanges, each of which includes an outer scroll having an abrupt change in its direction, the leading endof said scroll being positioned at the periphery of the disk and its trailing end being adjacent the center of the disk, the remaining scroll members of each set being positioned in the area defined by the outer scroll of the same set and the line connecting the ends of said outer scroll.

Another feature of the invention consists in providing the disk with a plurality of scrolls each having an abrupt change in its direction, the ends ofeach scroll being positioned on opposite sides of the diameter of the disk passing through the point of abrupt change in direction of the scroll and terminating on a line at the opposite side of the center of the disk from the point of abrupt change in direction of the scroll.

Another feature of the invention consists in providing the disks with a plurality of sets of scrolls each including an outer scroll having an abrupt change in its direction, the portion of each of said outer scrolls which extends inwardly from the point of abrupt change in direction forming with one of the scrolls of the next succeeding set a feed channel for an abrasive or other grinding material.

A .further feature of the invention consists in providing the polishing wheel with a plurality of sets ofscrolls each comprising an outer scroll having a portion extending inwardly toward the central portion of the disk and intervening in spaced :relation between the trailing end of a 1935, Serial No. 17,512

scroll of the same set and a scroll of the succeeding set and forming with the latter a channel for an abrasive or other grinding material.

Another feature of the invention consists in providing the polishing wheel with a plurality of sets of scrolls each comprising an outer scroll, an inner scroll and an intermediate scroll, the leading ends of said scrolls being spaced circumferentially of the disk, the leading end of said outer scroll terminating at the greatest distance from the center of the disk, and the leading end of the inner scroll terminating at a greater distance from the center of the disk than the leading end of the intermediate scroll.

A still further feature of the invention consists in providing the disk with a plurality of sets of scrolls each comprising a comparatively long outer scroll having an abrupt change in its direction dividing said scroll into two curved segments and a plurality ofshorter curved scrolls, the leading ends of which terminate inwardly of and adjacent to one of said segments and the trailing ends of which terminate adjacent the other of said segments on a line parallel to the line passing through the trailing ends of the shorter scroll of the opposite set, said segments forming arms embracing said shorter scrolls.

In the drawing illustrating a preferred construction:

Figure 1 is a bottom plan view of a polishing wheel embodying the invention.

Figure 2 is a side elevation of the wheel.

Figure 3 is a transverse section on the line 33, Figure 1.

In the drawing illustrating the invention, the scope whereof is pointed out in the claims, i indicates a circular rotatable disk provided at the center of its upper side with suitable means, such as perforated lugs 22, for the attachment of a driving shaft. These lugs are commonly secured to the body of the disk by being bolted thereto.

The disk I has attached to its lower or working face a plurality of scrolls or flanges, said scrolls being preferably bolted to the disk so as to be capable of being replaced when worn or broken.

In the form of the invention illustrated the scrolls are arranged in four similar sets, each set including an outer scroll 3 and a plurality of inner scrolls 4 and 5, respectively.

Each of the outer scrolls 3 has an abrupt change in its direction, as indicated at 6, said scroll thus being divided into two curved segments, an outer segment 7 and an inner segment 8 respectively. The eccentricity of the segment I of the outer scroll is much less than that of the segment 8 so that its angle of departure from the periphery of the disk I is relatively small as compared to that of the segment 8 and the point of abrupt change in the direction of the scroll is thus positioned nearer the periphery than the center of the disk. In the form of the invention shown in the drawing, the centers of curvature of the segments 1 and 8 of the outer scroll are respectively indicated at i and 8 The leading end of the outer scroll 3, which is preferably beveled, as indicated at 9, extends for a substantial distance in advance of the point of abrupt change in direction of the next preceding outer scroll and it terminates at or substantially at the periphery of the disk. Terminating the leading end of each outermost scroll 3 well in advance of the abrupt change in direction of the next preceding outer scroll 3 efficiently prevents the throwing of sludge from the wheel. The more eccentrically curved segment 8 is preferably of such length that its trailing end It) lies upon the same side of the center of the disk as does the leading end of the segment I, the leading end and the trailing end of the outer scroll being positioned on opposite sides of that diameter of the disk which passes through the point 6 of abrupt change in the direction of the scroll.

In addition to an outer scroll 3, each set of scrolls includes at least one inner scroll but preferably a plurality of inner scrolls, 4 and 5 respectively. These inner scrolls are positioned in the area defined by the outer scroll of the respectively corresponding set and the line connecting the leading end and the trailing end of such outer scroll, the outer scroll thus serving as a barrier preventing the inner scrolls from being thrown from the disk by centrifugal force in the event they are broken or torn loose from the disk by obstructions on the bed of stone being polished.

The leading ends of the inner scrolls 4 and 5 terminate adjacent the segment I of the outer scroll 3 and in spaced relation thereto, thus leaving a space or channel H for the passage of sludge, while the trailing ends thereof terminate adjacent the curved segment 8 of said outer scroll and in spaced relation thereto so as to leave a space or channel l2 for the passage of abrasive material. The trailing ends of the scrolls 4 and 5 and the trailing end it] of the outer scroll of the next preceding set preferably are disposed in a line parallel to a. line connecting the trailing ends of the corresponding inner scrolls of the opposite set. The leading ends of the inner scrolls 4 and 5 are spaced circumferentially of the disk and they are so positioned with respect to the outer scroll 3 that the leading end of the outer scroll terminates at the greatest distance from the center of the disk while the leading end of the inner most scroll 5 terminates at a greater distance from the center of the disk I than does the leading end of the intermediate scroll 4. The scrolls or flanges 4 and 5 have such an eccentricity with respect to the curved segment 1 of the outermost scroll of their set and with respect to the curved segment 8 of the outermost scroll of the next preceding set that the channels formed by said segments 1 and 8 and scrolls 4 and 5 progressively widen from their leading or intake ends toward their trailing or discharge ends, thus minimizing clogging of sludge in the polishing wheel.

The segment 8 of the outer scroll 3 of each set of scrolls intervenes between the trailing ends of the inner scrolls 4 and 5 of its set and the innermost scroll 5 of the next succeeding set. By this means, as well as due to the overlapping of the outer scrolls 3 themselves, the outer scrolls are prevented from being thrown from the disk in the event they should be torn loose therefrom, being prevented from being thrown outwardly by centrifugal force of the disk by the obstruction afforded by the inner scrolls or an outer scroll.

In the operation of the polishing wheel each set of scrolls acts as a feeder of sludge or abrasive material to the next succeeding set of scrolls, and the outer scroll of each set acts to gather and feed sludge not only to the next succeeding set, but to some extent to the opposite set of scrolls as well. While each outermost scroll 3 acts as a grinder throughout its entire length, its grinding effect is most decidedly augmented throughout the segment 8 thereof which extends inwardly toward the central portion of the disk. Sludge entering between the leading end of an outer scroll 3 of one set and the segment 1 of the outer scroll of the next preceding set passes along the channels formed by the segment 'I of the first named scroll, along the scrolls 4 and 5 of its set, and along the segment 8 of the next preceding set. In passing through these channels some grinding takes place as some of the sludge escapes from the channels and passes under the lower faces of the scrolls. Upon leaving the channels formed by the segments 1 and 8 and the intervening scrolls 4 and 5 the sludge encounters the barrier formed by the curved segment 8 of the including outer scroll of the same set. Due to the great eccentricity of this segment 8, a large part of the sludge passes thereunder to the next succeeding set of scrolls. Such sludge as does not escape under the curved segment 8 passes inwardly along the space or channel I2 between the trailing ends of the scrolls 4 and 5 and the segment 8, being guided by the latter and delivered from the inner end thereof.

A polishing wheel constructed in accordance with my invention materially reduces the time required to grind down a bed of stone and it leaves the bed in such excellent condition that less time and less material than has formerly been required is needed in finishing the work of polishing by subsequent processes.

I claim:

1. A polishing wheel embodying a rotatable disk having upon its working face a plurality of sets of scrolls, each set including an outer scroll and an inner scroll, said outer scroll terminating at its leading end at the periphery of the disk and terminating at its trailing end adjacent the center of the disk at a point substantially closer to said center than is the trailing end of said inner scroll and having an abrupt change in its direction, said leading end and said trailing end of said outer scroll being positioned on opposite sides of the diameter of the disk passing through said point of abrupt change in direction and said ends being positioned on a line which is on the opposite side of the center of the disk from said point of abrupt change in direction of the scroll.

2. A polishing wheel embodying a rotatable disk having upon its working face a plurality of sets of scrolls, each set including an outer scroll and a plurality of inner scrolls, the outer scroll of each set having a curved segment extending inwardly toward the central portion of the disk and intervening in spaced relation between the trailing ends of the inner scrolls of the same set and an inner scroll of the next succeeding set and also intervening between the trailing end of the inwardly extending segment of the outer scroll of the next preceding set and an inner scroll of the next succeeding set.

3. A polishing wheel embodying a rotatable disk having upon its working face a plurality of sets of scrolls, each set including an outer scroll and an inner scroll, each outer scroll having an abrupt change in its direction and extending inwardly from said point of change toward the central portion of the disk, said inwardly extending portion of said outer scroll lapping the inner scroll of the next succeeding set and forming therewith a channel for receiving grinding material, and also forming a barrier disposed substantially transverse of the inner scroll of the same set and of the inwardly extending portion of the outer scroll of the next preceding set.

4. A polishing wheel embodying a rotatable disk having upon its working face a plurality of sets of scrolls, each set including an inner scroll and an outer scroll having an abrupt change in its direction and extending inwardly from said point of change toward the central portion of the disk, the leading end of each of said outer scrolls terminating adjacent the periphery of the disk and substantially in advance of the point of abrupt change in direction of the outer scroll of the next preceding set, and the inwardly extending portion of each outer scroll lapping the inner scroll of the next succeeding set and forming therewith a channel for receiving grinding material, and also forming a barrier disposed substantially transverse of the inner scroll of the same set and of the inwardly extending portion of the outer scroll of the next preceding set.

5. A polishing wheel embodying a rotatable disk having upon its working face a plurality of sets of scrolls, each set including an inner scroll and an outer scroll, said outer scroll having an abrupt change in its direction at a point nearer the periphery than the center of the disk dividing it into an inner segment and an outer segment, said inner segment extending inwardly from said point of change toward the central portion of the disk, the leading end of each of said outer segments terminating adjacent the periphery of the disk and substantially in advance of the point of abrupt change in the direction of the outer scroll of the next preceding set, each of said inner scrolls being radially spaced be- 

